Summary: Zoospores of the fungus undergoing synchronous differentiation showed a rapid increase (250%) in phosphatidic acid (PA) concentration within 20 s of the inducing stimulus. There were only small (< 100%) changes in cGMP and cAMP and inositol phosphates during the same period. There was no consistent change in the concentration of diacyl glycerols during the first five minutes of differentiation. The addition of exogenous PA (3 mU) induced zoospore differentiation, with the optimum concentration dependent upon the Ca concentration in the suspension medium. Other phospholipids were ineffective as inducers. Both PA production and spore differentiation were Ca-dependent, and the addition of the Ca channel blocker verapamil, or the removal of exogenous Ca by EGTA addition, both reduced PA accumulation and slowed differentiation. We suggest that PA production in this organism arises via a stimulus-activated phospholipase D, and may act as a second messenger. There is no evidence for any role for cyclic nucleotides or inositol phosphates as second messengers during the early events of zoospore differentiation in this species.


Article metrics loading...

Loading full text...

Full text loading...


Most cited this month Most Cited RSS feed

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error